The present invention relates to a top end stop structure for a concealed slide fastener with zigzag or coil shaped filamentary fastener elements made of synthetic resin.
2. Description of the Related Art
One kind of top end stop structure for a concealed slide fastener is known (Japanese Utility Model Publication No. Sho 51-4819), in which a pair of bow-shaped pieces of synthetic resin are each fused across the legs and connecting portions of several of the fastener elements onto the upper end of the underside of the slide fastener. These synthetic resin pieces bow outwards so as to protrude in the same direction as the connecting portions away from the coupling heads of the fastener elements.
Another kind of top end stop structure for a concealed slide fastener is known (Japanese Patent Publication No. Sho 52-6656), in which a pair of top end stops are each formed from a lump of fusible material. The outer surface of this lump then coincides with the peak in the folded-in part at a respective one of successive space portions of the fastener chain. The inner surface then goes in between the tape and the edge of the folded-in part and extends beyond the outer edge of the folded-in part. At the other end there is a bow-shaped lip, the shape of which corresponds to that of the inner edge of the folded-in part of the tape.
A further top end stop structure for a slide fastener is known (Japanese Utility Model Laid-Open Publication No. Sho 62-148116), in which a flat piece of thermoplastic synthetic resin is bent into a U-shaped top end stop. This is then applied to the top end of each of opposite rows of fastener elements and is then fused in such a manner that its open ends fuse together through the fastener tape.
The concealed slide fastener top end stop described in the first publication is only fused onto one side of the fastener tape. This means that after long periods of use there is a strong possibility that it will fall away from that surface. Also, since the fastener elements and the fastener tape are parallel with each other, it is very difficult to insert such concealed slide fastener into the sewing machine foot guide.
Further, the concealed slide fastener described in the second publication is formed with a bow-shaped lip, the shape of which corresponds to that of the inner edge of the folded-in part of the fastener tape. Therefore, if its supporting area with respect to the fastener tape is increased , the angle between the supporting area and the tape has to be kept small, thus making the insertion of the concealed slide fastener into the sewing machine foot guide very difficult. Also, the top end stop is of the type inserted into the flanged part of the slider. This means that the pair of fastener tapes diverge at the openable side so that the slide fastener has an unpleasant external appearance.
The slide fastener top end stop described in the third publication is just the usual kind of top end stop and is not actually a top end stop for a concealed-type slide fastener. It therefore, cannot be expected to have the kind of construction like the one for the embodiment for this application where the U-shaped stopper part is held at a fixed angle with respect to the fastener elements. Also, the curved head of the U-shaped top end stop does not come into contact with the slider flange which makes the stopping function of the top end stop highly questionable.